Not long ago, reporters asked White House spokesman Jay Carney to react to Iran’s new “moderate” president Hassan Rouhani’s tweet that as a result of his negotiations with the United States, “world powers surrendered to Iran’s national will.”

Mr. Carney, speaking for the Obama administration, had an answer, “It doesn’t matter what they say. It matters what they do.”

In the context of world affairs, U.S. politicians have often made the mistake of assuming our adversaries don’t really mean what they say. We like to think that, in their hearts, they share our values and concerns.

In the 1930s, when Adolf Hitler talked about Jews and what should be done with them, Western leaders discounted his words as empty rhetoric.

When the Soviet Union’s Nikita Khrushchev thundered in the 1960s, “We will bury you,” U.S. politicians concluded he was posturing for domestic reasons and didn’t mean it.

Today, when extremist Middle Eastern leaders suggest that Israel should be destroyed, we comfort ourselves in the belief that they don’t really mean it.

History, contrary to Mr. Carney’s rhetoric, tells us that words do matter, and that we would be wise to listen to what our adversaries say because they may, in fact, act on what they say.

Of course, Mr. Carney’s rejoinder tells us more about the administration for which he speaks than about history and reality, but even here there is a truly serious disconnect.

Mr. Carney’s boss too often seems to think that his listeners should pay attention not to what he does, but to what he says, and that it is unfair of his critics to point out that his actions and words are often in conflict.

President Obama has stood behind a lot of teleprompters as candidate and president to deliver speeches and lectures that have meant very little. His words have contained promises he knew he couldn’t or had no intention of keeping and were seemingly forgotten as soon as they scrolled off the screen.

When his actions don’t jibe with his words, he and his defenders go back to revise the record and at times argue, as Obama defender Rep. Charles B. Rangel did at one point, that politicians shouldn’t be held accountable for what they say when they are campaigning.

Still, words matter even when those uttering them do so to mislead. The words provide insights as to the true feelings of the speaker. Thus, it was with Mr. Obama’s State of the Union speech last night.

It was the speech of a clearly frustrated leader who has always been uncomfortable with the need to work with others to accomplish his ends.

He continues to talk as if he has tried his best to work with Congress only to be constantly rebuffed by Republicans, who just don’t share his heartfelt desire to solve the nation’s problems.

Even those who complain about the partisanship of Republican leaders know this isn’t even a half-truth. This is a president who doesn’t even work well with members of his own party, let alone those of the opposition party.

He’s a leader who has been satisfied to give a speech and then sit back hoping someone, somewhere will translate his words into reality.

His failure thus far is evident in the polls. The American people don’t just disagree with much of what he’s tried to do.

They no longer trust him and aren’t certain he’s competent enough to accomplish much of anything.

Congressional members of his own party are beginning to pull away from him, and he’s rapidly becoming a lame duck as Democrats and Republicans alike begin looking to 2016.

It appears more and more likely that this fall will leave him with a Congress even less inclined to do his bidding.

All of this has made it clear to Mr. Obama and his advisers that anything he is to accomplish during the final years of his presidency will have to be accomplished by circumvention of a recalcitrant Congress.

While most presidents have used their State of the Union speeches to rather boringly present Congress with a “to do” list, this president has torn up the list and said, in essence, that he’ll just have to do it all himself.

This will give him a chance to rail on about those with whom he disagrees as he pursues an agenda that seeks not to transform, but to further divide the nation he promised to unite when he first ran for the presidency.

He has always been at his best when he’s been in campaign mode, belittling and questioning the motives, morals and integrity of his opponents.

He’s a president who needs an enemy.

He appears to think that by appealing to Americans’ economic frustrations that his own policies have made worse, he can make the successful class that enemy.

Follow-through, of course, is everything. Words, as Mr. Carney has warned us, are just words and don’t really matter.

Actions do, though, and if Mr. Obama follows through on his threat to govern by phone and pen, to ignore Congress and to implicitly emulate the style of authoritarian governments whose leaders don’t have to worry about legislatures, checks and balances, and the separation of powers that have limited the ability of U.S. presidents to “get things done,” we are in for a rough couple of years.

He may have been delivering his speech last night to Congress, but it would have been better suited for an “Occupy” rally of class warriors.